Tissue engineering involves the use of living cells to develop biological substitutes for tissue replacement. However, in order for tissue engineering to be practical, scaffolds must be developed that allow for tissue growth that approximates natural tissue growth.
Several techniques have been employed to develop tissue engineering scaffolds with varying degrees of success. For example, porous scaffolds composed of biodegradable polymers have found extensive use in the engineering of several tissue types (Hutmacher, D. W., “Scaffolds in tissue engineering bone and cartilage” Biomaterials 21:2529 2000; Chaignaud, B. E., et al., “The history of tissue engineering using synthetic biodegradable polymer scaffolds and cells” In: Atala, A., Mooney, D. J., eds. Synthetic biodegradable polymer scaffolds. Boston, Mass.: Birkhauser, 1997, pp. 1-14). Various tissue engineering strategies employ scaffolding materials as three-dimensional substrates either for in vitro cell seeding followed by transplantation (cell-based approaches), or as conductive and inductive substrates for direct implantation in vivo (conductive approaches) (Murphy, W. L. and Mooney, D. J., “Controlled delivery of inductive proteins, plasmid DNA and cells from tissue engineering matrices” J Periodontal Res 34:413 1999). The degree of success of these schemes depends, in part, on the internal structure of the scaffold system. Numerous applications require a highly interconnected, macroporous structure within a scaffold system to encourage neural and fibrovascular ingrowth, promote uniformity of cell seeding, and facilitate migration of both seeded cells and cells migrating from a contiguous in vivo site.
Scaffolds are built upon a framework. The framework helps regulate the interconnectivity of the scaffold material and pore size. After the scaffold is formed, the framework must be removed. Difficulties with current approaches of creating tissue engineering scaffolds referred to above include problems with consistency of final product, difficulties in regulating the scaffold interconnectivity and pore size and problems in eliminating the framework material after forming the scaffold.
What is needed is an economical method for creating functional tissue engineering scaffolds that are easy and inexpensive to produce, allow for consistency in scaffold interconnectivity and pore size and permits the easy elimination of the framework material after formation of the scaffold.